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Adaptive regions-of-interest camera operation for point-and-select luminaires Disclosure Number: IPCOM000187522D
Publication Date: 2009-Sep-10
Document File: 3 page(s) / 301K

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The Prior Art Database



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Adaptive regions-of-interest camera operation for point-and-select luminaires


    Communication of data via visible (LED) light, also known as Coded Light, has been proposed for lighting control and communication applications. In the former domain it is used for instance to indentify the addresses of luminaires during commissioning, or to read out status information. In the later domain, it can be used to replace RF communications. Challenge is in the efficient detection of the data from different luminaires.

To this end, we propose a camera-based detection method, based on conventional CMOS cameras. In this method, we first detect using normal imaging where the luminaires are located. This is done at normal camera rate, e.g. 50 Hz. Secondly, we analyze exclusively these regions-of-interest (ROI) using appropriate camera settings enabling to read-out the data of every luminaire sequentially in high speed, by adaptively reducing the number of pixels read out of the camera.


Pointing at luminaires to select them for control is a key enabling application for future lighting systems. For example, in a new home scene setting solution, luminaires can be selected by the user in a very intuitive way by pointing at them with a remote control. Similarly, the commissioning of lighting systems in office buildings can be greatly simplified by enabling the commissioning engineer to point and select the luminaires to retrieve their physical address.

Pointing at luminaires to select them for control can be enabled in a very simple (cost- effective) way by using Coded Light technology: every luminaire transmits a unique identifier, for example its network address, in the light output and a detector is used to measure these identifiers. When pointing the remote control to a luminaire, the detector will measure and detect its address and the luminaire will be selected.

In case more luminaires are present in the field of view of the detector, the light contributions of the various luminaires will sum up. Unless specific measures are taken, the sum of the contributions will result into an undetectable signal. This interference problem can be solved in two ways: by taking measures at the transmitter side or at the receiver side.

The transmitter side: luminaires transmit special codes that make them (quasi-)orthogonal and therefore interference free. This comes at the cost of longer transmission times (long codes with interference-free properties).

In parallel, visible light communications is being considered in IEE802 standardization for next generation high speed wireless communications. In this area the challenge is to achieve a high data rate, but also simultaneously detection of the data from different luminaires. Also, the alignment between transmitter and receiver is an important point there.

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Faster and parallel detection can be achieved by avoiding the use of...